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Title: Assay and properties of N-acetylglucosamine 6-phosphate deacetylase from rat liver

Conference · · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)
OSTI ID:6060601

N-Acetylglucosamine (GlcNAc) is generated, in liver and other tissues, as a product of the lysosomal degradation of complex carbohydrates. After diffusion into the cytosol, the monosaccharide is metabolized via catabolic or anabolic pathways, in which the first step is common to both pathways and consists of phosphorylation at C-6 by a specific GlcNAc kinase. When processed via the catabolic pathway, GlcNAc 6-phosphate is then deacetylated to glucosamine (GlcN) 6-phosphate. In the present study, they have developed a simple assay for the deacetylase catalyzing this reaction, in which /sup 3/H-acetate released from /sup 3/H-acetyl-labeled GlcNAc 6-phosphate is measured directly in a biphasic liquid scintillation counting system after acidification of the reaction mixture. The new assay has been used in partial purification of the deacetylase from rat liver and in analysis of kinetic and other properties of the enzyme. GlcN 6-phosphate and glucose 6-phosphate inhibited the deacetylase, while GlcNAc, GlcNAc 1-phosphate, GlcN 1-phosphate, and N-acetylgalactosamine had no effect. The activity of the enzyme was substantially inhibited by 5 mM Mn/sup 2 +/, Ni/sup 2 +/, or Cu/sup 2 +/, while Ca/sup 2 +/, Mg/sup 2 +/, and Ba/sup 2 +/ had essentially no effect at concentrations of 12.5 mM or lower. Co/sup 2 +/ stimulated at low concentrations (< 5 mM) but inhibited at higher concentrations. Gel chromatography on Sepharose CL-6B indicated that the enzyme had a mol. wt. greater than 160,000.

Research Organization:
Univ. of Alabama, Birmingham
OSTI ID:
6060601
Report Number(s):
CONF-870644-; TRN: 87-037629
Journal Information:
Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 46:6; Conference: 78. annual meeting of the American Society of Biological Chemists conference, Philadelphia, PA, USA, 7 Jun 1987
Country of Publication:
United States
Language:
English